Solomon’s seal sawfy
Solomon’s seal (Polygonatum x hybridum) is a beautiful shade-loving perennial that produces elegant arches of green foliage with pale bells dangling down at flowering time. It’s a very useful plant in a shady corner of the garden, but is commonly attacked by its own species of sawfly – Phymatocera aterrima – the larvae of which eat the leaves, resulting in a skeleton of stems and veins. The good news is that this usually happens once flowering has finished and it doesn’t kill the plant, which will emerge pristine the following spring.
Like all sawflies, this one is related to bees, and the female lays her eggs on plants using a saw-like organ. The eggs hatch into hungry grey caterpillar-like grubs with black heads. After feeding, the grubs drop into the soil to complete their lifecycle. The time to interrupt that cycle is when you see the grubs (from May). Although sprays are available, these also kill other insects. Picking the grubs off by hand ensures you don’t harm anything else. Most important is that you don’t accidentally kill any predators in your garden, because they will help to manage your sawfly population when you’re not watching.